Jim- Here's my understanding. Copyright and trademark law are two different things. Copyright applies to books, drawings, movies, music etc. For everything but books, current U.S. law is 75 years from creation. For example, Mickey Mouse was created in 1928, so the copyright runs out in 2003. I'm not sure when Gone With the Wind and Wizard of Oz were made, but their copyrights will also run out soon. Congress voted to extend the timeframe by 20 years. The law has been upheld in Appeals courts, but no teh Supreme Court has agreed to hear it. (For books, the protection goes from 50 years after the death of the author to 70 years)
I don't think many, and possibly none, of the stories Disney used would have been affected by the copyright extension. Still, just as their copyright on Mickey Mouse would be extended, so would the copyrights of everybody else's work. Its a level playing field.
Certainly Disney would benefit from this law, but they are hardly alone. Talking movies will be coming into play over the next 10 years, and movies like Gone and Wizard could become public property.
A trademark, on the other hand, is a symbol or phrase that a company uses as its identity. These do not expire. Disney MIGHT be able to use trademark law to protect Mickey Mouse, but I doubt they could pull it off with Donald Duck, Goofy, etc.
So unless something can be protected as a trademark, once its copyright expires, it can be used by whomever wants it. In the case of Mickey Mouse, he could be used for rat poison commercials, porno films, other amusement parks, etc. If you wanted to make your own Mickey Mouse t-shirt and sell it, you'd be free to do so, regardless of what Disney thought of its quality or appropriateness.